Análise dos parâmetros de síntese de NbN via reação gás-sólido

Abstract

The aim of this work is to study the synthesis of Niobium Nitride, starting from the precursor tris (oxalate) oxiniobate ammonium hydrate, through the gas-solid reaction in a fixed-bed reactor. The heat treatment reaction parameters to obtain the NbN were at temperatures 700, 800, 900 and 1000°C varying the time in the isotherm between 3, 4 and 5 hours. The gas mixture is composed of nitrogen and hydrogen. The composition and the total flow of the gas flow were varied, as well as the mass of the precursor used in the reaction. The obtained materials were characterized by X-ray diffraction (XRD), Rietveld Refinement and Scanning Electron Microscopy (SEM). Increasing the reaction temperature and time in the isotherm it was observed the phase change of niobium oxide to niobium nitride. There was formation of two phases of nitride, and the hexagonal phase is present in greater quantity, and the tetragonal phase in less quantity. With the higher flow rate, the high purity niobium nitride was obtained.